Equations of state for fluids based on hard sphere repulsion

2015 ◽  
Vol 29 (13) ◽  
pp. 1550089 ◽  
Author(s):  
Minhui Shan ◽  
Jianxiang Tian
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Hard Sphere ◽  
Equations Of State ◽  
The Past ◽  
Complex Interactions ◽  
Structures And Properties ◽  
The One ◽  
Real Fluids

As is well-known, the structures and thermodynamic properties of fluids are determined by the complex interactions, i.e., the repulsive one and the attractive one, among particles. The simplest equation-of-state (EOS) model maybe the one of hard sphere repulsion plus or multiplying some attraction. Followed by the rapid promotion of the accuracy of hard sphere EOS in the past dozens of years, one question rises as whether more accurate hard sphere repulsion derives better prediction of the structures and properties of fluids with a special attraction. In this work, we used two repulsions with clearly different accuracy and some attractions to construct series equations of state (EOSs) for real fluids, and then we discussed the saturated properties at liquid–gas equilibrium. We found that the answer to the question aforementioned is not definitely standing.

Thermodynamic properties of liquid mixtures: Selection of the pure liquid parameter

1974 ◽  
Vol 27 (3) ◽  
pp. 647 ◽  
Author(s):  
DV Fenby ◽  
NF Pasco
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Equations Of State ◽  
Liquid Mixtures ◽  
Pure Liquid ◽  
Excess Thermodynamic Properties ◽  
Pure Fluids ◽  
Liquid Parameter ◽  
Selection Of

There has recently been a revival of interest in theories of liquid mixtures based on analytic equations of state for pure fluids. We have shown that the method used to determine the parameters of the pure-liquid equation of state has a significant effect on the excess thermodynamic properties obtained from such theories.

Thermodynamic properties of conformal mixtures calculated from the hard-sphere equation of state

1973 ◽  
Vol 77 (18) ◽  
pp. 2212-2217 ◽  
Author(s):  
Aleksander Kreglewski ◽  
Randolph C. Wilhoit ◽  
Bruno J. Zwolinski
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Hard Sphere ◽  
Sphere Equation

An Equation of State for Compressed Water from 1 to 1000 Bar and from 0°C tO 150°C

1968 ◽  
Vol 10 (4) ◽  
pp. 319-328 ◽  
Author(s):  
M. R. Gibson ◽  
E. A. Bruges
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Equations Of State ◽  
Dynamic Properties ◽  
Similar Type ◽  
Independent Variables ◽  
Turbine Performance ◽  
Dependent Variables ◽  
Water Turbine ◽  
Water Substance

The precision with which the thermodynamic properties of compressed water and steam are known has led, not unnaturally, to the development of equations of state suitable only for use on electronic digital computers. The equations are in the main empirical although some are highly sophisticated and lead to lengthy programs and complex sub-routines. Among such equations are those of the 1966 and 1967 Formulations of the Thermo-dynamic Properties of Ordinary Water Substance prepared by the International Formulation Committee of the International Steam Conference. The favoured form of equation has been one in which the dependent variables are enthalpy, volume and entropy and the independent variables pressure and temperature. However, this form of equation may not prove to be always the most suitable and the purpose of this paper is to describe how another type of equation, in which the dependent variable is enthalpy and the independent variables are pressure and entropy, may be established and applied. It is believed that this particular type of equation, relating as it does the three most important parameters in pump and turbine performance, has special qualities for design and efficiency calculations. By way of example the efficiency of a water turbine is evaluated according to the ‘thermodynamic method’ described by Thom (2). A concluding section outlines the further steps being taken by the authors to provide a similar type of equation over ranges of pressure and temperature up to 1000 bar and 1000°C.

scholarly journals QUARK–DIQUARK EQUATIONS OF STATE MODELS: THE ROLE OF INTERACTIONS

2003 ◽  
Vol 12 (03) ◽  
pp. 519-526 ◽  
Author(s):  
J. E. HORVATH ◽  
G. LUGONES ◽  
J. A. DE FREITAS PACHECO
Keyword(s):  
Equation Of State ◽  
Boundary Conditions ◽  
Neutron Stars ◽  
Hard Sphere ◽  
Degrees Of Freedom ◽  
Equations Of State ◽  
Compact Star ◽  
Star Models ◽  
State Models

Recent observational data suggests a high compacticity (the quotient M/R) of some "neutron" stars. Motivated by these works we revisit models based on quark–diquark degrees of freedom and address the question of whether that matter is stable against diquark disassembling and hadronization within the different models. We find that equations of state modeled as effective λϕ4 theories do not generally produce stable self-bound matter and are not suitable for constructing very compact star models, that is the matter would decay into neutron matter. We also discuss some insights obtained by including hard sphere terms in the equation of state to model repulsive interactions. We finally compare the resulting equations of state with previous models and emphasize the role of the boundary conditions at the surface of compact self-bound stars, features of a possible normal crust of the latter and related topics.

scholarly journals Approaching mercury distribution in burial environment using PLS-R modelling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noemi Álvarez-Fernández ◽  
Antonio Martínez Cortizas ◽  
Zaira García-López ◽  
Olalla López-Costas
Keyword(s):  
Soft Tissues ◽  
Primary Source ◽  
Secondary Source ◽  
Sources Of Information ◽  
Mercury Distribution ◽  
The Past ◽  
Complex Interactions ◽  
Target Organs ◽  
History Of ◽  
The One

AbstractMercury environmental cycle and toxicology have been widely researched. Given the long history of mercury pollution, researching mercury trends in the past can help to understand its behaviour in the present. Archaeological skeletons have been found to be useful sources of information regarding mercury loads in the past. In our study we applied a soil multi-sampling approach in two burials dated to the 5th to 6th centuries AD. PLRS modelling was used to elucidate the factors controlling mercury distribution. The model explains 72% of mercury variance and suggests that mercury accumulation in the burial soils is the result of complex interactions. The decomposition of the bodies not only was the primary source of mercury to the soil but also responsible for the pedogenetic transformation of the sediments and the formation of soil components with the ability to retain mercury. The amount of soft tissues and bone mass also resulted in differences between burials, indicating that the skeletons were a primary/secondary source of mercury to the soil (i.e. temporary sink). Within burial variability seems to depend on the proximity of the soil to the thoracic area, where the main mercury target organs were located. We also conclude that, in coarse textured soils, as the ones studied in this investigation, the finer fraction (i.e. silt + clay) should be analysed, as it is the most reactive and the one with the higher potential to provide information on metal cycling and incipient soil processes. Finally, our study stresses the need to characterise the burial soil environment in order to fully understand the role of the interactions between soil and skeleton in mercury cycling in burial contexts.

Thermodynamic excess functions of regular and related solutions according to some equations of state based on the perturbed hard sphere model

1973 ◽  
Vol 26 (10) ◽  
pp. 2071 ◽  
Author(s):  
DK Astin ◽  
ID Watson
Keyword(s):  
Equation Of State ◽  
Hard Sphere ◽  
Equations Of State ◽  
Fluid Model ◽  
Quantitative Agreement ◽  
Excess Functions ◽  
Hard Sphere Model ◽  
Thermodynamic Excess Functions ◽  
Two Fluid Model ◽  
Two Fluid

The excess thermodynamic functions of 12 mixtures, each representative of a certain type of system, have been calculated by means of the van der Waals, Frisch,1 and Carnahan and Starling2 equation of state, in conjunction with one-fluid and two-fluid models of conformal mixtures. In addition, the equation of state of hard sphere mixtures of Mansoori et al.3 has been used. Though none of the approaches give quantitative agreement for any of the systems considered, they all give a qualitative account which broadly reflect the trends in behaviour. In the cases where it is appropriate to comment on the qualitative accuracy the two-fluid model, used with either the Frisch or Carnahan and Starling equation of state, shows a slight superiority to the others.

Renormalization Group Theory Applied to the CPA Equation of State: Impacts on Phase Equilibrium and Derivative Properties

2019 ◽  
Author(s):  
Gabriel Silva ◽  
Charlles Abreu ◽  
Frederico W. Tavares
Keyword(s):  
Renormalization Group ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Chemical Engineering ◽  
Equations Of State ◽  
Thermodynamic Description ◽  
Critical Conditions ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Vapor Liquid

Calculation of thermodynamic properties such as vapor-liquid phase behavior with equations of state is largely and successfully employed in chemical engineering applications.<br>However, in the proximities of the critical point, the different density-fluctuation scales inherent to critical phenomena introduce significant changes in these thermodynamic properties, with which the classical equations of state are not prepared to deal.<br>Aiming at correcting this failure, we apply a renormalization-group methodology to the CPA equation of state in order to improve the thermodynamic description in the vicinity of critical points.<br>We use this approach to compute vapor-liquid equilibrium of pure components and binary mixtures, as well as derivative properties such as speed of sound and heat capacity.<br>Our results show that this methodology is able to provide an equation of state with the correct non-classical behavior, thus bringing it in consonance with experimental observation of vapor-liquid equilibrium and derivative properties in near-critical conditions.

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